J.A.M. wrote:

mmm... IMHO you shouldn't buy the cheapest. You are improving your vision,

Ok, on a more serious level:

Look for good UV filtering,

UV filtering isn't an issue anymore. It was at the time when sunglasses
consisted of coated glass. Todays poly-whatever glasses filter out
essentially all UV, regardless of colour or price. You could even fly
without sunglasses, as even the canopy filters between 80 and 90 percent
of the UV.

good contrast,

This is an important point. Look for glasses that filter out the blue.
They will appear yellow, brown or red. This will give you contrast and
cuts the haze to some degree.

no color alteration,

Colour alteration isn't an issue. Your brain will adapt pretty fast to
whatever filter you put on your nose.

and feel comfortable with them (good brightness filtering)

Probably the most important point.

Stefan